Such an automatic system is already known (Modern Plastics Encyclopedia, 1982-1983, Page 363). Since the mandrel is extracted from the hardened structural part directly after leaving the furnace, it is, however, only possible to manufacture, with the conventional system, structural parts having a very specific winding structure, namely a winding structure having a uniform inside diameter. A finish-working of the structural part is intended in the conventional system after the mandrel has been extracted.
It is known from German OS No. 25 24 853 to accelerate the winding of light masts of fiber-reinforced plastic by providing a winding machine with several winding mandrels arranged parallel to one another.
British Pat. No. 1 478 231 discloses a substantially automated system for the manufacture of pipe-shaped or tubular structural parts. Felt-strip sections which are soaked with a binding agent are thereby fed to a winding mandrel, which mandrel is heated up in order to harden the inside of the structural part during the winding operation. After the winding is done, several pressure rollers arranged around the structural part hold the structural part in position while the winding mandrel is extracted from the structural part. Through the hardened inside, the structural part temporarily maintains its form and is then fed to a furnace to complete the hardening process and thence to the finish-working devices. The transport through the furnace, which has several levels, occurs thereby through crossbeams which move wavelike up and down in the conveying direction, so that the structural parts rotate at the same time. The structural parts drop thereby from one level to the other level. However, it is not possible to manufacture structural parts having wound fiber strands thereon with the conventional system.
The basic purpose of the invention is to provide an automatic system having a high performance characteristic to facilitate the manufacture of pipe-shaped or tubular structural parts of any desired winding structure.